USE OF THE MCNP-POLIMI CODE FOR THE EVALUATION OF CROSS TALK EVENTS IN LARGE SCINTILLATION DETECTORS

Cross talk effects are important in physics experiments that make use of adjacent non-capture detectors. This paper presents the use of the MCNP-PoliMi code and its postprocessor to evaluate the effect of cross-talk among neighboring cells in a liquid scintillating detector array, and between two detector arrays separated by a distance of 50 cm. Cross talk occurs when the same particle registers a pulse in two or more neighboring cells. In time-dependent coincidence measurements with fissile material, the occurrence of cross-talk events is undesirable because it generates correlated events that are unrelated to the spontaneous and induced fission events that are to be measured. A technique to simulate and evaluate cross-talk effects is presented. The capability of the MCNP-PoliMi code to track particles scattering between adjacent detectors can be applied to other experiments in which detector arrays are used. Although cross talk between adjacent detectors is significant, that between detectors placed on opposite sides of a container is less than 1%, and therefore not important.